In this article, we propose a new excited state dynamics mechanism for quinoline-pyrazole isomers (QP-1 and QP-2) in the liquid phase based on the time-dependent density functional theory (TD-DFT) method. The calculated potential energy curve shows that QP-2 is more likely to occur as an excited state intramolecular proton-transfer (ESIPT) process than QP-1, whereas QP-2 will occur as a twisted intramolecular charge transfer (TICT) process, which is also the main decay pathway of QP-2 fluorescence quenching. The TICT process is not involved in QP-1 due to the high energy barrier. Based on excited state energy decomposition and charge decomposition analysis, it is determined that the energy gap and hole-electron interaction are the main driving forces that can cause the TICT process to occur. These results are inconsistent with the conclusions of recent theoretical reports [J. Phys. https://www.selleckchem.com/products/ly2880070.html Chem. A 2015, 119, 6269-6247], in which the authors proposed that QP-2 will not twist after proton transfer (PT-2) in the lowest singlet excited state, and its fluorescence quenching pathway is the rapid intersystem crossing. We found that the reason for this difference was that the author did not consider the solvent effects in the calculations. Moreover, the rapid intersystem crossing of QP-2 is invalidated by computing the spin-orbit coupling between singlet and triplet excited states. Considering the fact that the spectral data of QP isomers were obtained in solution, our calculation results should be more in line with the experimental requirements, so as to further provide help for the reasonable explanation of the experimental mechanism and the detailed description of the theoretical calculation.Medium resolution (Δν? ? 3 GHz) laser-induced fluorescence (LIF) excitation spectra of a rotationally cold sample of YbOH in the 17300-17950 cm-1 range have been recorded using two-dimensional (excitation and dispersed fluorescence) spectroscopy. High resolution (Δλ ? 0.65 nm) dispersed laser-induced fluorescence (DLIF) spectra and radiative decay curves of numerous bands detected in the medium resolution LIF excitation spectra were recorded. The vibronic energy levels of the X?2Σ+ state were predicted using a discrete variable representation approach and compared with observations. The radiative decay curves were analyzed to produce fluorescence lifetimes. DLIF spectra resulting from high resolution (Δν? less then 10 MHz) LIF excitation of individual low-rotational lines in the ?Ã2Π1/2(0,0,0)-X?2Σ+(0,0,0), Ã2Π1/2(1,0,0)-X?2Σ+(0,0,0), and [17.73]Ω = 0.5(0,0,0)-X?2Σ+(0,0,0) bands were also recorded. The DLIF spectra were analyzed to determine branching ratios which were combined with radiative lifetimes to obtain transition dipole moments. The implications for laser cooling and trapping of YbOH are discussed.The interaction of soil organic matter with mineral surfaces is a critical reaction involved in many ecosystem services, including stabilization of organic matter in the terrestrial carbon pool and bioavailability of plant nutrients. Using model organic acids typically present in soil solutions, this study couples laboratory adsorption studies with density functional theory (DFT) to provide physical insights into the nature of the chemical bonding between carboxylate functional groups and a model FeOOH cluster. Topological determination of electron density at bond critical points using quantum theory of atoms in molecules (QTAIM) analysis revealed that the presence of multiple bonding paths between the organic acid and the FeOOH cluster is essential in determining the competitive adsorption of organic acids and phosphate for FeOOH surface adsorption sites. The electron density and Laplacian parameter values from QTAIM indicated that the primary carboxylate-FeOOH bond was more ionic than covalent in nature. The experimental and computational results provide molecular-level evidence of the important role of electrostatic forces in the bonding between carboxylic acids and Fe-hydroxides. This knowledge may assist in the formulation of management studies to meet the challenges of maintaining ecosystems services in the face of a changing climate.Designing a molecular switch with bistable on/off states is of particular interest in molecular electronics. Motivated by experimental studies of molecular conductors, interplays of photons and electrons and their effects on electrical properties are studied theoretically. We have tried to model a molecular optical switch based on DNA sequences of the hepatitis delta virus and Toxocara canis parasite. The electrical response of chains to the light irradiation was examined to optimize the function of an optical switch. The switch turns on when the amplitude of incident irradiation and its frequency approach to 0.3 at the unit of (?c)/(er0) and 2 THz, respectively. We can modulate the switching of the system via the simultaneous variation of effective factors and obtain different islands in the parameter settings. The appearance of different islands in the parameter surface relates to the on/off states of electrical current, which can be verified and estimated through the multifractal analysis.The electric field experienced by the OH group of phenol embedded in the cluster of ammonia molecules depends on the relative orientation of the ammonia molecules, and a critical field of 236 MV cm-1 is essential for the transfer of a proton from phenol to the surrounding ammonia cluster. However, exceptions to this rule were observed, which indicates that the projection of the solvent electric field over the O-H bond is not a definite descriptor of the proton transfer reaction. Therefore, a critical electric field is necessary, but it is not a sufficient condition for the proton abstraction. This, in combination with an adequate solvation of the acceptor ammonia molecule in a triple donor motif that energetically favors the proton transfer process, constitutes necessary and sufficient conditions for the spontaneous proton abstraction. The proton transfer process in phenol-(ammonia)n clusters is statistically favored to occur away from the plane of the phenyl ring and follows a curvilinear path which includes the O-H bond elongation and out-of-plane movement of the proton.